Micrometer caliper



2 Sheets-Sheet 1 Jan. 5', 1932. M. K. PARKHURST MICROMETER CALIPER FiledMarch 10. 1928 Jan. 5, 193'2. PARKHURST 1,840,276

MICROMETER C-AL IPER Filed Marph 10, 1928 2 Sheets-Sheet 2 EL-12L ure 3;

Patented Jan. 5, 1932 UNITED STATES PATENT OFFICE MALCOLM K. PARKHURST,OF NEW YORK, N. Y., ASSIGNOR TO BROWN & SHARPE MFG.

' (20., OF PROVIDENCE, RHODE ISLAND MICROMETER CALIBER Applicationfiled. March 10, 1928. Serial N0.-260,588.

This invention relates to certain new and useful improvements inmicrometer calipers, and the primary object thereof is to provide ac'aliper which can be accurately read thereby positively eliminating'anyguess work on the part of the operator.

It frequently occurs that the marks from zero upward on the outer sleevecome to a position in which the lines of reading are between two of themarks, and the user ordinarily then guesses as to what the reading mightbe. The present invention therefore aims to eliminate this guess work bythe provision of an auxiliary sleeve, the reading line of which ismovable by virtue of rotation of the auxiliary sleeve so that thereadings on I the latter will indicate the exact reading in connectionwith the reading of the outer sleeve. The invention, therefore,eliminates the disadvantages heretofore had with the ordinary verniermicrometer caliper, the three outstanding disadvantages of which havebeen the inconvenience of having to compare a number of l1nes 1ndetermlmng the reading;

the annoyance of having to reverse the micrometer, or turn same over inorder to read same; and finally the necessity of removing the micrometerin gauging large or stationary work. In the latter regard, it will beun-,

derstood that insuch instances, which are very common, the practice ofsetting the clamp ring and then removing the micrometer' seriouslyaffects the accuracy of a preci- -sion instrument, which procedure alsohas a detrimental effect in causing undue wear on 'boththe anvil and thespindle. I

l In the drawings Figure 1 is a side elevationof the invention, p

Figure 2 is a rearendelevation; Figure 3 is a view'similar to Figurelpart- 1y broken away and in section, and

on line 44 of Fig- Figure 4 is a section Inproceeding in accordance withthe present invention, the usual yoke v1 is employed having an anvil 2at one end, which is opposed by the customary spindle 3. The spindle 3has a'barrel or sleeve 4associated therewith,

which latter has the customary graduations or readings 5, the largesub-divisions of which may be divided into .10 inches and the smallersub-divisions into 025 inches and further has a rotatable barrel orsleeve 6 provided with graduations or reading lines 7 substantiallydivided into 25 divisions which cooperate with the fixed lines of thebarrel 4. I

A yoke 8 is connected to the main yoke 1 and is preferably partiallyinset with relation to the latter, as shown in Figure 3 and is securedin position by means of ascrew 9. The yoke has a sleeve 10 which isreceived in a hole 11 provided therefor in one of the sides of the armof the yoke, which sleeve provides a bearing for the inner end of aspindle 12, the latter carrying a spool 13, the spool being tensioned bymeans of a coil spring 14.

In accordance with the present invention, the barrel 4: instead of beingfixed as in the prior art, is capable of slight oscillatory movement andaccordingly same has a rigid arm 15 connected thereto by means of whichoscillatory movement is imparted to the barrel 4. The arm 15 has aforked end 16 which latter straddles a pin 17 eccentrically mountedonthe spool 13. A stop pin 18'is carried by the yoke 8 and is adapted toengage one side of the arm 15 to limit movement of the latter in onedirection. The pin 17 is formed integral with the spindle, and thelatter has a collar 18 at the outer end of the pin 17, the collar inturn being integral with the enlarged outer end 19 of the spindle. Anauxiliary barrel 20 comprising an auxiliary measuring means is fixed onthe outer end of the spindle and is held against the collar 18 by meansof a screw 21. The barrel has graduations 22 thereon which are adaptedto 90 register with a fixed reading line 23 on the yoke 8 as depicted inFigure 1. The small oscillatory barrel or sleeve 20 is graduated O, 1,2, 3, 1, 5, 6, 7, 8, 9,0, each graduation corresponding to 1/10,000. Thecomplete range from 0 to 0 is covered by but one-half a revolution ofthis oscillatory sleeve, the spring 14 maintaining the barrel directlyon the 0 nearest 9.

It will be noted that the sleeve 4 is independently mounted and directlyconnected to the auxiliary structure by means of the tion by reason ofthe spring action of the auxiliary member throughthe lever 15.

In operation, the micrometer is set, for example, to give a reading of.27 67 7, the os-' cillatory sleeve 'remaining in its normal position,whereupon it will be seen that the coincidence line on the barrel 4;does not quite coincide with the .002 mark on the barrel 6'. Theoscillatory. barrel 20 is now turned, whereupon the coincidence line onthe barrel 4; approaches the .002 mark on the barrel 6. At a point 7 or.0007 on the barrel 20, the coincidence line on the barrel 4 is indirect alignment with the line on the barrel 6. Thus it is merelynecessary to add the .0007 to the original reading of .276 which gives.2767.

V s is evident, there is no advancement of the spindle 3 upon turningthe oscillatory barrel 20, the sole function of the latter being merelyto gauge by teirtliousandths any discrepancy of exact alignment betweenthe coincidence line on the barrel 4 and a onethousandth mark on thebarrel 6.

It will be noted that in turningthe barrel 20, same rotates barrel 4 inthe same direction, as that of barrel 20, this eliminates any tendencyof the'barrel 20 to loosen and thereby give an incorrect reading. Byvirtue of the automatic restoration to normal or neutral of the barrel20, there can be no error due to forgetfulness 011 the part of the useraccordingly. Should measurements of .001 only be taken, then the usualprocedure is followed, the barrel 20 being disregarded. Having thusdescribed my invention what I claim as new and desire to secure byLetters Patent is 1.111, a micrometer caliper, a yoke'having I an anvil,a spindle carried by said yoke, an

oscillating sleeve on the spindle, a graduated rotary sleeve on thefirst named sleeve and fixed to said spindle,a yoke fixedly carried bythe main yoke and having areading line, an auxiliary graduated sleeve, aspindle con.- nected to the second yoke and having the aux- I iliarysleeve fixed thereonin cooperating relation to said reading line, aslotted arm fixed on the oscillatory sleeve, a spool, on the secondspindle, tensioning means for said spool, a collar on the second spindleand having an eccentric pin engaged in the slot of said arm, and a stopfor the arm carried by the second yoke.

2. In a micrometer caliper, a yoke having an anvil, a spindle carried bysaid yoke, a a

graduated oscillatory sleeve on the spindle, a graduated-rotary sleeveonthe first sleeve and fixed to said spindle, a member fixedly i d b thyoke and having a reading line,

anarm fixed on the oscillatory sleeve, a spindle carried by said member,an auxiliary sleeve fixed on the second spindle and having 'graduationscooperating with saidreading line, means carried by said second spindleto engage and operate the arm upon turning of the auxiliary sleeve, andspring tensioned means for the second spindle to restore the latter andthereby the auxiliary sleeve to normal position subsequent to operationof the latter,

. 3. In combination with a caliper having a rotary graduated. sleeve andan oscillatory graduated. sleeve cooperating therewith, a graduatedauxiliary sleeve disposed adjacent the first named sleeve, said caliperhaving a fixed reading line for cooperation with the auxiliary sleeve,means connected to the auxiliary and oscillatory sleeves tooperate thelatter by the former, and means to automatically restore the said twolast named sleeves to normal position subsequent to operation thereof. 7

4. In combination with a caliper having a pair of cooperating graduatedsleeves each rotatable independently of the other, auxiliary means toread measurements between the graduations of said sleeves and meansactuated by said auxiliary means to effect relative turning movement ofone of the sleeves independent of the other to bring the saidgraduat-ions of the sleeves into register thereby to enable readingOfthe difference betweensaid graduations on the auxiliary means. 7

5. In combination with a caliper'having graduated main measuring means,auxiliary measuringmeans, and means operable by the auxiliary means toefiectregister of the graduations ofthe main measuring means thereby toindicate on the auxiliary measuring means the, measurement existingbetween adjacent graduations of the main measuring means so as toenablereading of said measurement on the auxiliary means, and means toautomatically restore theauxiliarymeans to normal position subsequent tooperation thereof.

6. In combination with a caliper having a pair of cooperating graduatedrelatively rotatable sleeves, l auxiliary means to read measurementsbetween the graduations of its pairof cooperatingmovable means forobtaining primary measurements, auxiliary means a for obtainingsecondary measurements, means to -mount the auxiliary means formovement,;means connected to one of the pair of means and to theauxiliary means for effecting movement of one of said pair of means bymovement of auxiliary means independently of the other of said movablemeans, and means for restoring the auxiliary means and thereby said oneof the pair of means to initial position following operation of theauxiliary means.

8. In combination with a caliper having a pair of cooperating means eachmovable independently of the other for obtain ng primary measurements,auxiliary means for obtaining secondary measurements, means to mount theauxiliary means for movement,

and means connected to one of the pair of means and to the auxiliarymeans for effecting movement of said one means independently of theother of said movable means by the auxiliary means.

9. In combination with a caliper having rotary graduated sleeve and anoscillatory graduated sleeve cooperating therewith, a graduatedauxiliary sleev'e disposed adjacent the first named sleeve,said caliperhaving a fixed reading line for cooperation with the auxiliary sleeve,means connected to the auxiliary and oscillatory sleeves to operate thelatter by the former independently of said rotary graduated sleeve andmeans to automatically restore the oscillatory and auxiliary sleeves tonormal position subsequent to operation thereof.

10. In a caliper of the character described, a rotatable spindle, agraduated sleeve fixed to said spindle, a graduated oscillatory sleevewithin said rotatable sleeve, auxiliary measuringmeans, means connectingthe oscillatory sleeve and auxiliary measuring means whereby to movesaid oscillatory sleeve independently of the rotatable sleeve toindicate measurements existing between the graduations on the spindlesleeve and the oscillatory sleeve and means to automatically restore theoscillatory sleeve and auxiliary measuring means to normal position.

In testimony whereof I have signed my name .to this specification.

MALCOLM K. PARKHURST.

